“First and foremost, Subtraction is an exciting and indelibly tense piece of genre cinema. It is only after its crescendo of an ending that the questions it poses start coming to mind.”

Farzaneh (Taraneh Alidoosti) is a driving instructor in Tehran. While at work, she follows her husband Jalal (Navid Mohammadzadeh) as he seems to meet up with another woman. She sends her father-in-law to confront her, but he discovers that the truth is even more unsettling. The man she followed, Mohsen, and his wife, Bita, are Farzaneh and Jalal’s doppelgängers. The likeness, however, stops at the physical.

Farzaneh and Jalal are a working-class couple. She’s three months pregnant and the doctor has advised her to stop taking anxiety medication as it may harm the baby. Disturbed by what she perceives as hallucinations, she wants to resume taking the meds but Jalal, a gentle and caring husband, dissuades her. Struggling with the situation, Farzaneh spirals into depression.

Bita and Mohsen are much better off, and they already have a child, but they’re facing a predicament of their own. Mohsen had beaten up an older colleague after he accused him of corruption. He refuses to apologize and the family faces having to leave Tehran. Alienated by her stern husband, Bita finds comfort in striking up a friendship with Jalal. It is he who suggests impersonating Mohsen to issue the apology. They embark on what will obviously be a dangerous game with severe consequences.

The premise requires some suspension of disbelief, and some viewers may struggle with the situation remaining unexplained. Apart from a futile attempt by Farzaneh to discover whether she and Bita could be sisters, the characters don’t even seem particularly interested in getting to the bottom of things. It hardly matters, however, as the character drama that develops is much more fascinating than it would be if the movie attempted a logical explanation.

Early on, we hear the saying: “The grass is always greener on the other side”, and it turns out to be a sort of warning as Bita and Jalal grow ever closer. His compassion makes Bita feel safer than with her aggressive husband. Her laugh reminds Jalal of Farzaneh as she used to be years ago. They both seem to have encountered superior versions of their partners. While they remain faithful, the seed of the question “what if?” has been planted and there’s no turning back.

Subtraction is an expertly crafted film. The screenplay deftly balances the four perspectives of our main characters while keeping the audience guessing until the end. Director Mani Haghighi and cinematographer Morteza Najafi achieve tension with superb framing while the play of light and darkness visualizes the topic of identity. Editor Meysam Molaei paces the film perfectly, relentlessly moving forward, providing strong accents with several stunning transitions and allowing room for reflection by leaving the screen dark in several key moments.

The film is no less a showcase for the lead actors, engrossing in their dual roles. Mohammadzadeh plays Mohsen as a menacing figure, his posture and coldness implying superiority over everyone around him. He impresses even more as Jalal, his wide-eyed approachability constantly bordering on naivety but never veering into simple-mindedness. Alidoosti provides the film its emotional anchor with Bita, her generosity revealing a kind heart while her reserved reactions betray the consequences of years living with a tyrant. Her Farzaneh, on the other hand, is a quietly heartbreaking portrayal of a broken soul, weighed down by her body, her mind and the merciless world she lives in.

It always rains in the world Subtraction inhabits. An aesthetic choice that offers a somewhat harrowing atmosphere but perhaps also a hint that the story is disconnected from reality. The opposing view is presented by the outsider’s perspective of Bita and Mohsen’s son who senses that something is off even though he doesn’t understand it. The audience is made aware of how perceptive he is, but his own father remains ignorant, possibly leading to his downfall.

There are warning signs all over the place. The film’s most prominent message warns against idealizing your partner, focusing on their best side while ignoring their negative qualities to the point of a broken relationship. A closer look offers several more: an unhealthy obsession with yourself, ignoring the well-being of the mother in favour of the unborn child, the blindness of jealousy, the toxicity of pride. There is also a hint of social commentary on the roles of men and women in Iranian society. Yet it never feels like Haghighi is preaching to us. First and foremost, Subtraction is an exciting and indelibly tense piece of genre cinema. It is only after its crescendo of an ending that the questions it poses start coming to mind.